熱血的小葉老師的圖學筆記 Week06

Week06 打光

gist.github.com 可以分享程式碼如下

Week06 打光

jsyeh.org/3dcg10 下載 data win32

windows.zip => 下載\windows\Light Material.exe

data.zip    => 下載\windows\data\模型

主角 Light Material.exe

(左上)左鍵drag可旋轉

(左上)右鍵,換模型

(左下)右鍵,換 Material 

(以下程式碼都不用寫)(都用剪貼的)

右邊的參數 glLightfv(...) 的 fv 是 float vector (陣列)

GLfloat light_pos[] = {-2.0, 2.0, 2.0, 1.0 }; 陣列

glLightfv(GL_LIGHT0, GL_POSITION, 陣列)

          第幾個燈

                     設定它的位置

## step01-2

講解光的性質(位置, Ambient, Diffuse, Specular), 講解glLightfv()的參數意思,了解fv是有小數點的陣列, 了解 GL_POSITION可以設定光的位置.

## step01-3

講解完程式碼, 接下來是偷程式碼時間。File-New-Project 選 GLUT專案, 就好了。接下來Ctrl-F找關鍵字light 找到 (1) 有陣列宣告、(2)有函式呼叫 就這樣。

實作時間:

0. freeglut 裝好, lib 改一下 libglut32.a

1. File-New-Project, GLUT專案 沒了....

2. 從 GLUT 範例 偷程式碼!!! Ctrl-F 找 light

3. (1) 有陣列宣告、(2)有函式呼叫

```C++

const GLfloat light_ambient[]  = { 0.0f, 0.0f, 0.0f, 1.0f };

const GLfloat light_diffuse[]  = { 1.0f, 1.0f, 1.0f, 1.0f };

const GLfloat light_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };

const GLfloat light_position[] = { 2.0f, 5.0f, 5.0f, 0.0f };

const GLfloat mat_ambient[]    = { 0.7f, 0.7f, 0.7f, 1.0f };

const GLfloat mat_diffuse[]    = { 0.8f, 0.8f, 0.8f, 1.0f };

const GLfloat mat_specular[]   = { 1.0f, 1.0f, 1.0f, 1.0f };

const GLfloat high_shininess[] = { 100.0f };

```

```C++

    glEnable(GL_DEPTH_TEST);

    glDepthFunc(GL_LESS);

    glEnable(GL_LIGHT0);

    glEnable(GL_NORMALIZE);

    glEnable(GL_COLOR_MATERIAL);

    glEnable(GL_LIGHTING);

    glLightfv(GL_LIGHT0, GL_AMBIENT,  light_ambient);

    glLightfv(GL_LIGHT0, GL_DIFFUSE,  light_diffuse);

    glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);

    glLightfv(GL_LIGHT0, GL_POSITION, light_position);

    glMaterialfv(GL_FRONT, GL_AMBIENT,   mat_ambient);

    glMaterialfv(GL_FRONT, GL_DIFFUSE,   mat_diffuse);

    glMaterialfv(GL_FRONT, GL_SPECULAR,  mat_specular);

    glMaterialfv(GL_FRONT, GL_SHININESS, high_shininess);

```

## step02-1

結合之前 GLUT 10行茶壼程式, 配合打光的程式碼 8+10行, 做出打光的茶壼, 其中光的位置有稍微調一下z的值

```C++

#include <GL/glut.h>

const GLfloat light_ambient[]  = { 0.0f, 0.0f, 0.0f, 1.0f };

const GLfloat light_diffuse[]  = { 1.0f, 1.0f, 1.0f, 1.0f };

const GLfloat light_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };

const GLfloat light_position[] = { 2.0f, 5.0f, -5.0f, 0.0f };

const GLfloat mat_ambient[]    = { 0.7f, 0.7f, 0.7f, 1.0f };

const GLfloat mat_diffuse[]    = { 0.8f, 0.8f, 0.8f, 1.0f };

const GLfloat mat_specular[]   = { 1.0f, 1.0f, 1.0f, 1.0f };

const GLfloat high_shininess[] = { 100.0f };

void display()

{

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        glColor3f(1, 1, 0);

        glutSolidTeapot( 0.3 );

    glutSwapBuffers();

}

int main( int argc, char** argv )

{

    glutInit( &argc, argv);

    glutInitDisplayMode( GLUT_DOUBLE | GLUT_DEPTH );

    glutCreateWindow("week06 light");

    glutDisplayFunc(display);

    ///偷來的程式,要放 glutCreateWindow()之後,才會有效

    glEnable(GL_DEPTH_TEST);

    glDepthFunc(GL_LESS);

    glEnable(GL_LIGHT0);

    glEnable(GL_NORMALIZE);

    glEnable(GL_COLOR_MATERIAL);

    glEnable(GL_LIGHTING);

    glLightfv(GL_LIGHT0, GL_AMBIENT,  light_ambient);

    glLightfv(GL_LIGHT0, GL_DIFFUSE,  light_diffuse);

    glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);

    glLightfv(GL_LIGHT0, GL_POSITION, light_position);

    glMaterialfv(GL_FRONT, GL_AMBIENT,   mat_ambient);

    glMaterialfv(GL_FRONT, GL_DIFFUSE,   mat_diffuse);

    glMaterialfv(GL_FRONT, GL_SPECULAR,  mat_specular);

    glMaterialfv(GL_FRONT, GL_SHININESS, high_shininess);

    ///放在 glutMainLoop()之前

    glutMainLoop();///卡在這裡,之後的程式,都不會執行到

}

```

step02-2

week06_light_mouse_motion_rotate

```C++

#include <GL/glut.h>

#include <stdio.h>

const GLfloat light_ambient[]  = { 0.0f, 0.0f, 0.0f, 1.0f };

const GLfloat light_diffuse[]  = { 1.0f, 1.0f, 1.0f, 1.0f };

const GLfloat light_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };

const GLfloat light_position[] = { 2.0f, 5.0f, -5.0f, 0.0f };

const GLfloat mat_ambient[]    = { 0.7f, 0.7f, 0.7f, 1.0f };

const GLfloat mat_diffuse[]    = { 0.8f, 0.8f, 0.8f, 1.0f };

const GLfloat mat_specular[]   = { 1.0f, 1.0f, 1.0f, 1.0f };

const GLfloat high_shininess[] = { 100.0f };

float x=150, y=150, z=0, scale=1.0;

int oldX=0, oldY=0;

void display()

{

    glClearColor( 0.5, 0.5, 0.5, 1 );///R,G,B,A 其中A半透明功能,目前沒開

    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);

    glPushMatrix();///備份矩陣

        glTranslatef( (x-150)/150.0 , -(y-150)/150.0 ,z);

        glScalef(scale, scale, scale);///都縮放成 scale倍

        glColor3f(1,1,0);///黃色的

        glutSolidTeapot( 0.3 );///茶壼

    glPopMatrix();///還原矩陣

    glutSwapBuffers();

}

void keyboard( unsigned char key, int mouseX, int mouseY )

{

}

void mouse(int button, int state, int mouseX, int mouseY )

{///為了解決瞬間移動的錯誤,我們改用正確的方法

    oldX = mouseX; oldY = mouseY;

}

void motion(int mouseX, int mouseY)

{

    if( mouseX-oldX > 0 ) scale *= 1.01;

    if( mouseX-oldX < 0 ) scale *= 0.99;

    ///x += (mouseX-oldX);  y += (mouseY-oldY);

    oldX = mouseX;       oldY = mouseY;

    display();

}

int main(int argc, char**argv)

{

    glutInit(&argc, argv);

    glutInitDisplayMode(GLUT_DOUBLE|GLUT_DEPTH);

    glutCreateWindow("week05 keyboard");

    glutDisplayFunc(display);

    glutKeyboardFunc(keyboard);///今天的主角

    glutMouseFunc(mouse);///上上週的主角

    glutMotionFunc(motion);///上週的主角

    ///偷來的程式,要放 glutCreateWindow()之後,才會有效

    //glEnable(GL_DEPTH_TEST);

    glDepthFunc(GL_LESS);

    glEnable(GL_LIGHT0);

    glEnable(GL_NORMALIZE);

    glEnable(GL_COLOR_MATERIAL);

    glEnable(GL_LIGHTING);

    glLightfv(GL_LIGHT0, GL_AMBIENT,  light_ambient);

    glLightfv(GL_LIGHT0, GL_DIFFUSE,  light_diffuse);

    glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);

    glLightfv(GL_LIGHT0, GL_POSITION, light_position);

    glMaterialfv(GL_FRONT, GL_AMBIENT,   mat_ambient);

    glMaterialfv(GL_FRONT, GL_DIFFUSE,   mat_diffuse);

    glMaterialfv(GL_FRONT, GL_SPECULAR,  mat_specular);

    glMaterialfv(GL_FRONT, GL_SHININESS, high_shininess);

    ///放在 glutMainLoop()之前

    glutMainLoop();

}

```

## step03-1 講解法向量

## step03-2 期中考題

```C++

glPushMatrix();///備份矩陣 10

  glTranslatef(x,y,z);//移動 10

  glRotatef(角度,x,y,z);//旋轉 10

  glScalef(x,y,z);//縮放 10

  glBegin(GL_POLYGON);//開始畫 10

    glColor3f(r,g,b);//色彩 10

    glNormal3f(nx,ny,nz);//打光的法向量

    glTexCoord2f(tx,ty);//貼圖座標

    glVertex3f(x,y,z);//頂點 10

  glEnd();

glPopMatrix();///還原矩陣 10

```

## step03-3

今天最後一節課,想要整合打光+上週教的程式,所以讓同學接續前一個打光的程式,加上旋轉的效果

```C++

#include <GL/glut.h>

#include <stdio.h>

const GLfloat light_ambient[]  = { 0.0f, 0.0f, 0.0f, 1.0f };

const GLfloat light_diffuse[]  = { 1.0f, 1.0f, 1.0f, 1.0f };

const GLfloat light_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };

const GLfloat light_position[] = { 2.0f, 5.0f, -5.0f, 0.0f };

const GLfloat mat_ambient[]    = { 0.7f, 0.7f, 0.7f, 1.0f };

const GLfloat mat_diffuse[]    = { 0.8f, 0.8f, 0.8f, 1.0f };

const GLfloat mat_specular[]   = { 1.0f, 1.0f, 1.0f, 1.0f };

const GLfloat high_shininess[] = { 100.0f };

float x=150, y=150, z=0, scale=1.0, angle=0.0;

int oldX=0, oldY=0;

void display()

{

    glClearColor( 0.5, 0.5, 0.5, 1 );///R,G,B,A 其中A半透明功能,目前沒開

    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);

    glPushMatrix();///備份矩陣

        glTranslatef( (x-150)/150.0 , -(y-150)/150.0 ,z);

        glRotatef(angle, 0,1,0);///對Y軸轉動

        glScalef(scale, scale, scale);///都縮放成 scale倍

        glColor3f(1,1,0);///黃色的

        glutSolidTeapot( 0.3 );///茶壼

    glPopMatrix();///還原矩陣

    glutSwapBuffers();

}

void keyboard( unsigned char key, int mouseX, int mouseY )

{

}

void mouse(int button, int state, int mouseX, int mouseY )

{///為了解決瞬間移動的錯誤,我們改用正確的方法

    oldX = mouseX; oldY = mouseY;

}

void motion(int mouseX, int mouseY)

{

    angle += (mouseX-oldX);///轉動

    ///if( mouseX-oldX > 0 ) scale *= 1.01; ///縮放

    ///if( mouseX-oldX < 0 ) scale *= 0.99;

    ///x += (mouseX-oldX);  y += (mouseY-oldY);//移動

    oldX = mouseX;       oldY = mouseY;

    display();

}

int main(int argc, char**argv)

{

    glutInit(&argc, argv);

    glutInitDisplayMode(GLUT_DOUBLE|GLUT_DEPTH);

    glutCreateWindow("week05 keyboard");

    glutDisplayFunc(display);

    glutKeyboardFunc(keyboard);///今天的主角

    glutMouseFunc(mouse);///上上週的主角

    glutMotionFunc(motion);///上週的主角

    ///偷來的程式,要放 glutCreateWindow()之後,才會有效

    //glEnable(GL_DEPTH_TEST);

    glDepthFunc(GL_LESS);

    glEnable(GL_LIGHT0);

    glEnable(GL_NORMALIZE);

    glEnable(GL_COLOR_MATERIAL);

    glEnable(GL_LIGHTING);

    glLightfv(GL_LIGHT0, GL_AMBIENT,  light_ambient);

    glLightfv(GL_LIGHT0, GL_DIFFUSE,  light_diffuse);

    glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);

    glLightfv(GL_LIGHT0, GL_POSITION, light_position);

    glMaterialfv(GL_FRONT, GL_AMBIENT,   mat_ambient);

    glMaterialfv(GL_FRONT, GL_DIFFUSE,   mat_diffuse);

    glMaterialfv(GL_FRONT, GL_SPECULAR,  mat_specular);

    glMaterialfv(GL_FRONT, GL_SHININESS, high_shininess);

    ///放在 glutMainLoop()之前

    glutMainLoop();

}

```

## step03-4

今天最後一個程式,把剛剛的程式,整合成 week06_light_keyboard_mouse_motion_all 可以利用keyboard切換now的值,來做移動、旋轉、縮放。.zip

```C++

#include <GL/glut.h>

#include <stdio.h>

const GLfloat light_ambient[]  = { 0.0f, 0.0f, 0.0f, 1.0f };

const GLfloat light_diffuse[]  = { 1.0f, 1.0f, 1.0f, 1.0f };

const GLfloat light_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };

const GLfloat light_position[] = { 2.0f, 5.0f, -5.0f, 0.0f };

const GLfloat mat_ambient[]    = { 0.7f, 0.7f, 0.7f, 1.0f };

const GLfloat mat_diffuse[]    = { 0.8f, 0.8f, 0.8f, 1.0f };

const GLfloat mat_specular[]   = { 1.0f, 1.0f, 1.0f, 1.0f };

const GLfloat high_shininess[] = { 100.0f };

float x=150, y=150, z=0, scale=1.0, angle=0.0;

int oldX=0, oldY=0, now=1;///now: 1移動, 2轉動, 3縮放

void display()

{

    glClearColor( 0.5, 0.5, 0.5, 1 );///R,G,B,A 其中A半透明功能,目前沒開

    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);

    glPushMatrix();///備份矩陣

        glTranslatef( (x-150)/150.0 , -(y-150)/150.0 ,z);

        glRotatef(angle, 0,1,0);///對Y軸轉動

        glScalef(scale, scale, scale);///都縮放成 scale倍

        glColor3f(1,1,0);///黃色的

        glutSolidTeapot( 0.3 );///茶壼

    glPopMatrix();///還原矩陣

    glutSwapBuffers();

}

void keyboard( unsigned char key, int mouseX, int mouseY )

{

    if(key=='1' || key=='w' || key=='W') now=1;///移動

    if(key=='2' || key=='e' || key=='E') now=2;///轉動

    if(key=='3' || key=='r' || key=='R') now=3;///縮放

}

void mouse(int button, int state, int mouseX, int mouseY )

{///為了解決瞬間移動的錯誤,我們改用正確的方法

    oldX = mouseX; oldY = mouseY;

}

void motion(int mouseX, int mouseY)

{

    if(now==1){///移動

        x += (mouseX-oldX);  y += (mouseY-oldY);///移動

    }else if(now==2){///轉動

        angle += (mouseX-oldX);///轉動

    }else if(now==3){

        if( mouseX-oldX > 0 ) scale *= 1.01; ///縮放

        if( mouseX-oldX < 0 ) scale *= 0.99;

    }

    oldX = mouseX;       oldY = mouseY;

    display();

}

int main(int argc, char**argv)

{

    glutInit(&argc, argv);

    glutInitDisplayMode(GLUT_DOUBLE|GLUT_DEPTH);

    glutCreateWindow("week05 keyboard");

    glutDisplayFunc(display);

    glutKeyboardFunc(keyboard);///今天的主角

    glutMouseFunc(mouse);///上上週的主角

    glutMotionFunc(motion);///上週的主角

    ///偷來的程式,要放 glutCreateWindow()之後,才會有效

    glEnable(GL_DEPTH_TEST);

    glDepthFunc(GL_LESS);

    glEnable(GL_LIGHT0);

    glEnable(GL_NORMALIZE);

    glEnable(GL_COLOR_MATERIAL);

    glEnable(GL_LIGHTING);

    glLightfv(GL_LIGHT0, GL_AMBIENT,  light_ambient);

    glLightfv(GL_LIGHT0, GL_DIFFUSE,  light_diffuse);

    glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);

    glLightfv(GL_LIGHT0, GL_POSITION, light_position);

    glMaterialfv(GL_FRONT, GL_AMBIENT,   mat_ambient);

    glMaterialfv(GL_FRONT, GL_DIFFUSE,   mat_diffuse);

    glMaterialfv(GL_FRONT, GL_SPECULAR,  mat_specular);

    glMaterialfv(GL_FRONT, GL_SHININESS, high_shininess);

    ///放在 glutMainLoop()之前

    glutMainLoop();

}

```